Toward Commercialization of the Beta-Alumina Family of Ionic Conductors

Abstract

The beta-alumina family of materials has played a central role in the field of solid-state ionics. β- and β-alumina have been a principal theme in the field ever since Yao and Kummer reported the extraordinarily high conductivity for sodium β-alumina. The material “came of age” at a time when there was great interest in the science and technology of highconductivity solid electrolytes. A previous MRS Bulletin review introduced this broad family of materials, examining the range of compositions and the two major structures. The beta-alumina family emerged as almost an ideal system in which to explore structure-property relations, as its unusual structure is responsible for its remarkable ion-transport properties. Although the initial interest in this material, and the one which endures to this day, is its rapid sodium-ion transport, the rich ion-exchange chemistry added a dimension to this material that few inorganic systems can match, let alone exceed. β-alumina, in particular, is an almost universal solid electrolyte for cations. It constitutes a broad family of solid electrolytes whose properties are dependent upon the nature of the ion inserted into the conduction plane. As a result, the β-aluminas have served as model systems for a wide range of studies: proton transport and mixed-ion diffusion, order-disorder reactions, and superlattice phenomena. Moreover, these β-alumina compositions demonstrated that fast-ion transport was not limited to a few monovalentions, but could be extended to divalent and even trivalent cations. With the latter materials, the interest was not necessarily ion transport, but optical properties instead. The presence of trivalent cations in this unusual structure, coupled with the ability to control the chemistry of the local environment, enabled the β-aluminas to exhibit a number of novel optical properties.

Electrical properties of sodium beta-alumina ceramics synthesized by citrate sol-gel route using glycerine

“…The lowest activation energy was calculated for the Mg-SBA ceramics prepared from the S-114 powders calcined at 1100°C and sintering at 1500°C for 10 h, which can be attributed to the presence of higher portion of β ′′ phase and higher density. The obtained conductivity values of the Mg-SBA ceramics are in good agreement with those cited in literature, and even higher than the published results [14][15][16][17]. Thus, the electrical conductivity at 300°C reported by Avinash et al [18] is about 0.065 S/cm which is almost one order of magnitude lower than the values reported in this work.…”

The primate appendix: A reassessment

“…Although the application scale of the NGK NAS batteries expanded year by year and especially increased sharply in the last 3–5 years, the large‐scale commercialization of NAS batteries still demands better performances, safety improvements, and level of automation in the fabrication of high‐quality ceramics for cost reduction, which depends on the development of new functional materials and novel cell designs 8, 9…”

Mixed potential protonic?electronic conductivity in the Dion?Jacobson-type layered perovskites in hydrogen-containing atmosphere and their application in ammonia sensors

“…The required gas composition was obtained by diluting commercially available 1000 ppm of ammonia in argon with pure argon gas using Tylan mass flow controllers. [11,15,16] with those of h-aluminas [19]. …”

“…The electrical conductivities of a few D-J-type layered perovskites are compared in Fig. 2 with those of h-aluminas [19]. We see that the electrical conductivities of the D-J phases are much lower than those of h-aluminas.…”